P0711

Diagnostic Chart:

CIRCUIT DESCRIPTION

The Automatic Transmission Fluid Temperature (TFT) sensor is a negative coefficient thermistor. When the transmission fluid is cold, the sensor resistance is high. As the transmission fluid warms up, the sensor resistance decreases. This diagnostic monitors the TFT circuit. The circuit may be functional, but not in the normal operating range. This diagnostic indicates stuck, erratic, intermittent, or skewed values, indicating poor system performance. The TFT range is -40 to +151°C (-40 to +305°F).

When the Powertrain Control Module (PCM) detects an intermittent voltage or no voltage change in the TFT sensor circuit, then DTC P0711 sets. DTC P0711 is a Type B DTC.

CONDITIONS FOR SETTING THE DTC

^ No ECT DTCs P0116, P0117, P0118, P1114 or P1115.

^ No VSS DTCs P0502 or P0503.

^ No Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) DTCs P0716 or P0717.

^ The system voltage is 10-17 volts.

^ The transmission fluid temperature is -37 to 149°C (-35 to 300°F).

^ The transmission fluid temperature at start-up is -40 to 21°C (-40 to 70°F).

^ The engine run time is greater than 15 minutes.

^ The vehicle speed is greater than 24 km/h (15 mph) for 2 minutes and 30 seconds.

^ The Torque Converter Clutch (TCC) slip is greater than 4 RPM for 1 second.

^ The engine coolant temperature is greater than 70°C (158°F).

^ The engine coolant temperature has changed by 50°C (90°F) since start-up.

Failure Criteria:

Case 1

The change in transmission fluid temperature since start-up is less than 1.5°C (2°F) for 4 minutes and 14 seconds.

Case 2

The change in transmission fluid temperature is greater than 20°C (36°F) within 200 milliseconds; 14 times within 7 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ If any engine coolant temperature sensor codes set, the PCM substitutes a transmission fluid temperature default value of 132°C (269°F).

^ If the engine coolant temperature is greater than 115°C (239°F), the PCM substitutes a transmission fluid temperature default value of 132°C (269°F). This enables transmission Hot Mode. The transmission remains in Hot Mode until the engine coolant temperature drops below 110°C (230°F).

^ If the engine run time is less than 3 minutes, the PCM substitutes the intake air temperature for the transmission fluid temperature value at ignition ON.

^ If the engine coolant temperature is 45-115°C (115-239°F), the transmission fluid default temperature equals ECT-10°C when the intake air temperature is less than 27°C (81°F) at ignition ON. If the intake air temperature is greater than 27°C (81°F) at ignition ON, the transmission fluid default temperature equals ECT+10°C.

^ If the engine run time is greater than 3 minutes and the engine coolant temperature is less than 45°C (113°F), the PCM substitutes a transmission fluid temperature default value of 12°C (54°F).

^ DTC P0711 is stored in the PCM history.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

^ The PCM cancels the DTC default functions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS

^ Inspect the wiring for poor electrical connections at the PCM, the transmission 20-way connector, the TFT sensor 2-way connector and all other circuit connecting points for the following conditions:

- A bent terminal

- A backed out terminal

- A damaged terminal

- Poor terminal tension

- A chafed wire

- A broken wire inside the insulation

- Moisture intrusion

- Corrosion

^ Test the TFT sensor at various temperature levels to evaluate the possibility of a skewed (mis-scaled) sensor.

^ When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

^ Inspect the transmission 20-way connector for transmission fluid.

TEST DESCRIPTION

The numbers below refer to the step numbers on the Diagnostic Table.

5. This step tests for an intermittent short or open condition in the engine wiring harness. The test light is used as a resistor in the circuit.

6. This step determines if the PCM or the TFT sensor is causing a steady, unchanging TFT reading.